Process for breaking petroleum emulsions



Patented July 22, 1941 PROCESS FOR BREAKING PETROLEUM EMULSIONS Melvin De Groote, University City, and Bernhard Keiser, Webster Groves, Mo., assignors to Petrolite Corporation, Ltd., Wilmington, DeL, a

corporation of Delaware No Drawing. Application June 27, 1940, Serial No. 342,718

6 Claims.

This invention relates primarily to the resolution of petroleum emulsions.

One. object of our invention is to provide a novel process for resolving petroleum emulsions of the water-in-oil type, that are commonly referred to as cut oil, roily oil, emulsified oil, etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed in a more or less permanent state throughout the oil whichconstitutes the continuous phase of the emulsion.

Another object of our invention is to provide an economical and rapid process for separating emulsions which have been prepared under controlled conditions from mineral oil, such as crude petroleum and relatively soft waters or weak brines. Controlled emulsification and subsequent demulsification under the conditions just mentioned is of significant value in removing impurities, particularly inorganic salts, from pipeline oil.

We have found that if the ricinoleic acid condensation product or esterification product derived by reaction between ricinoleic acid or a ricinoleic acid body of the kind subsequently described, is reacted with tris(hydroxymethyl) aminomethane, or a homolog or analog thereof, as subsequently described, one obtains a new composition of matter which has unusual efiectiveness as a demulsifier for petroleum emulsions.

Reactions of the kind just referred to are concerned with the introduction of anacyl radical, for instance, a ricinoleyl radical into an amine of the kind mentioned. Such acylation may take place by virtue of an amidification reaction, or 1 by virtue of an esterificati'on reaction. For the sake of convenience, in the hereto appended claims both types of reactions, amidification and esterification will be referred to as acylation reactions. In other words, reference to an acylation reaction is not intended to differentiate between whether an esterification reaction takes place or an amidification reaction takes place or 1: both take place.

Ricinoleic acid is most readily available in the form of castor oil, which contains about 85% triricinolein. Instead of ricinoleic acid, one may employ monoricinolein, diricinolein, methyl ricinoleate, ethyl ricinoleate, benzyl ricinoleate, cyclohexyl ricinoleate, etc. Similarly, one may employ polyricinoleic acid, such as diri cinoleie acid, triricinoleic, and tetraricinoleic acid; or one may employ the dibasic type of diricinoleic acid. Obviously, ricinoleic acid esters can be derived from polyhydric alcohols other than glycerol, for instance, from the various glycols, polyglycols, polyglycerols, methyl glycerol, and the like. Ordinarily, one would employ the cheapest source of the ricinoleic acid radical, which is castor oil. Slightly blown castor oil or the like may be used.

Castor oil can be treated with one mole ortwo moles of glycerol or any intermediate quantity,

to produce a material consisting largely of diricinolein, monoricinolein, and some triricinolein, with perhaps a small amount of free glycerol; Such material is commonly referred to as superglycerinated castor oil or superglycerinated triricinolein. Such mixture may be considered as a typical ricinoleic acid body.

Having indicated the variety of ricinoleic acid compounds which may be employed toproduce the new compound or material that is used as a demulsifier in practising our process, referencewill now be made to the type of amine intended for reaction. It is well known that paraflins can be treated with nitric acid, so as to produce nitroparaflins or nitrites. Such nitroparafi'lns canbe treated with aldehydes, particularly aliphatic aldehydes, having four carbon atoms or less, so as to produce nitroparafiins in which one, two or three hydroxyl alkyl radicals have been'introduced, and particularly characterized by the fact that such nitroparaffins may have two or'three alkylol groups attached to the same carbon atom. Such nitropararllns can readily be converted into the corresponding amine. See Chemical Industries, volume 45, No. 7, pages 664-668, December, 1939. See also Industrial and Engineering Chemistry, volume 32, No. 1, page 34.

Some known examples of amines of the kind described are:

2-am1'no-2-mcthyl-l,3-propancdiol 2-amino-2-ethyl-l,3-propanodio Nllz NH: CllzOl'lCJCllzOll CHzOHCHzOH CH3 52H:

Tris (hydroxymcthyl) aminomethanc Such amines may be indicated by the following formula type:

C-NHz in which D represents a divalent radical, such as the methylene radical, and T may be a hydrogen atom or the same as OHD, or may represent a monovalent hydrocarbon radical, particularly an alkyl radical. In other words, the nature of T may vary with the particular parafiin selected, and the molal reaction ratio between the nitroparaflin and aldehyde in the event the paraffin is methane. Needless to say, such reactions between an aldehyde and a nitroparaflin may yield a monohydric alcohol, as distinguished from a nitro-diol or nitro-triol, in the event the paraffin is methane. Such monohydroxylated compound can be converted into an alkylolamine. Such alkylolamine, as, for example Z-amino-l-butanol, is not herein contemplated for reaction with condensation products or esterification products of the kind previously described. Of various aldehydes employed for reaction with the nitroparaflins, formaldehyde, acetaldehyde, and butyraldehyde are to be preferred. with formaldehyde being particularly desirable. Cyclic aldehydes, such as benzaldehyde or hexahydrobenzaldehyde, give very inferior yields.

Having obtained an amine of the kind above described, which is a primary amine, it can readily be converted into a secondary or tertiary amine by any of the procedures commonly employed for introducing an alkyl or similar monovalent hydrocarbon radical. By means of suitable alkylating agents, one may introduce alkyl groups, aryl radicals, aralkyl radicals, alicyclic radicals, hydroxy hydrocarbon radicals, and the like. Convenient reagents for such reactions include alkyl chlorides, such as butyl chloride, benzyl chloride, phenyl chloride, ethyl bromide, glycerol chlorhydrin, ethylene chlorhydrin, ethylene oxide, propylene oxide, diethyl sulfate, ethyl chloracetate, etc. The result of an alkylation reaction or the equivalent usually results in the formation of an amine salt, such as the amine hydrochloride. The liberation of the free amine depends on conventional treatment with caustic soda or the like. Treatment with a reactive alkylene oxide, such as ethylene oxide, propylene oxide, and the like does not result in the formation of a salt, and thus in many ways is a more suitable procedure. It should be noted that the hydroxyl, which is part of the radical OH.D, is reactive towards alkylating agents. In some instances, perhaps such hydroxyl hydrogen atom is more reactive than in the amino hydrogen atom, and perhaps in other instances, not so reactive. The speed .of the reactions depends, of course, on the reactants selected and the conditions of the reaction.. However, it is to be noted that such reaction may result in the formation of an ether group. This may be illustrated by involving a butyl chloride and a hydroxyl hydrogen atom, thus:

C-NH:

OH.D

In this instance the radical C4H9.O.D. represents an alkoxy alkyl radical, in which D might be obtained from any one of the aldehydes mentioned, for example, acetaldehyde or butyraldehyde; and the butyl radical might be replaced by some other radical, such as the hexyl radical, benzyl radical, cyclohexyl radical, or the like.

If ethylene oxide, propylene oxide, or the like are used to react with the hydrogen atom previously referred to, then the reaction proceeds as follows:

Thus, examining the class of compounds in the broadest aspect, they may be rewritten as:

B r z in which B represents a monovalent hydroxy hydrocarbon radical, preferably an alkylol radical, or may be a monovalent oxyhydrocarbon radical, in which the carbon atom chain is interrupted at least once by an oxygen atom, or may be a hydroxylated oxyhydrocarbon radical, which, in addition to having at least one hydroxyl radical, has the carbon atom chain interrupted at least once by an oxygenatom. Reactants such as glycerol monochlorhydrin or the corresponding chlorhydrins derived from dior tri-glycerol, would permit the introduction of radicals containing more than one hydroxyl group, and being interrupted more than once by an oxygen atom. T may be the same as B, or may be a hydrogen atom or any alkyl radical. Z represents a hydrogen atom, or may represent any monovalent hydrocarbon radical, hydroxy hydrocarbon radical, hydroxy oxyhydrocarbon radical, characterized by having a hydroxyl radical, and having a carbon atom chain interrupted at least once by oxygen, or a radical derived by hypothetical removal of alpha hydrogen atom from a carboxy acid ester. It is to be noted that the preferred amine is of the type which contains no aryl radicals, particularly no aryl radicals attached to the amino nitrogen atom, and is preferably of the primary amine type. Due to its availability, the amine, which we prefer to employ is tris (hydroxymethyl) aminomethane.

It is obvious, in view of what has been said, that the acylation products obtained may be of the type in-which all acyl radicals present are in the amido form. Compounds may be of the type in which all acyl radicals present are in the ester form. It is also possible to have a series of compounds which exhibit both the amido form and the ester form. Furthermore, it is obvious that an amine of the kind contemplated cannot react with a ricinoleic acid body, unless there is present either an alcoholiform hydroxy, or an amino hydrogen atom. 01' course, both forms of reactive hydrogen atoms maybe present, a hydrogen of the alcoholic radical being referred to as a reactive hydrogen atom.. With this in mind, in the hereto appended claimsthe expression acylation-reactive amine is employed to designate such amine which is reactive in regard to acylation reactions of the kind .described.

As is apparent to a person skilled in the art of acylation reactions of the kind referred to, one can select reactants and conditions of reaction so as to obtain primarily one particular type or primarily another particular type. These variations will be described in some of the following examples of our new composition of matter:

- Example 1 A molecular proportion of tris(hydroxymethyl)methyl dibutylamine is treated with onemole of ricinoleic acid and heated until one obtains an ester with the elimination of water. Insofar that the original amine employed contains no replaceable amino hydrogen atom, obviously, the only compound obtainable is the ester form.

Example 2 A molecular proportion of tris(hydroxvmethyl) methyl butylamine is treated with 1 mole of ricinoleic acid and heated until one obtains an ester with the elimination of water.

Example 3 A molecular proportion of tris(hydroxymethyDmethyl butylamine is treated with one mile ofethyl ricinoleate. The esters preferentially react with replacement of an amino hydrogen atom, rather than an alcoholiform hydroxyl hydrogen atom. Thus, the above reaction can be conducted in a manner to produce the amide in almost complete absence of the ester.

Example 4 Example 5 One molecular proportion of tris(hydroxymethyDaminomethane is treated with two moles of ricinoleic acid until one forms the amide ester. Theoretically, one can form a secondary amide, i. e., an amide in which two amino hydrogen atoms attached to the same amino nitrogen atom have been replaced by an acyl radical. However, the introduction of the second amide group attached to the same amino nitrogen, is rather difficult to realize under ordinary conditions of reaction; and thus, actually one introduces the second acyl group in the ester form.

Example 6 Tris(butyloxymethyl) aminomethane is treated with one mole of ricinoleic acid to form the corresponding amide of the following formula:

(C-iHBOCHz)3CN in which OCR represents the acyl radical derived from ricinoleic acid. If a slightly additional amount of ricinoleic acid is employed, and if conditions producing acylation are raised to a point just short of decomposition temperature and reaction is continued for a long while, one

obtains a minor proportion of the secondary amide of the following composition:

ployed is that apparently there is an equilibrium characterized by the presence of a basic or moderately basic amino type of compound naturally can be used as such (without reaction with water); or it can be used in the form of a base,

that is, the compound derived by reaction with water, or in the form of a salt, for instance, the acetate or the salt derived by reaction with a strong mineral acid, such as hydrochloric acid or the like.

Conventional demulsifying agents employed in the treatment of oil field emulsions are used as such, or after dilution with any suitable solvent, such as water, petroleum hydrocarbons, such as gasoline, kerosene, stove oil, a coal tar product, such as benzene, toluene, xylene, tar acid oil, cresol, anthracene oil, etc. Alcohols, particularly aliphatic alcohols, such as methyl alcohol, ethyl alcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, etc., may be employed as diluents. Miscellaneous solvents, such as pine oil, carbon tetrachloride, sulfur dioxide extract obtained in the refining of petroleum, etc, may be employed as diluents. Similarly, the material or materials employed as the demulsifying agent of our process may be admixed with one or more of the solvents customarily used in connection with conventional demulsifying agents. Moreover, said material or materials may be used alone, or in admixture with other suitable well known classes of demulsifying agents.

It is well known that conventional demulsifying agents may be used in a water-soluble form, or in an oil-soluble form, or in a form exhibiting both oil and water solubility. However, since such reagents are sometimes used in a ratio of 1 to 10,000 or 1 to 20,000, or even 1 to 30,000, such an apparent insolubility in oil and water is not significant, because said reagents undoubtedly have solubility within the concentration employed. This same fact is true in regard to the material or materials employed as the demulsifying agent of our process.

We desire to point out that the superiority of the reagent or demulsifying agent contemplated in our process is based upon its ability to treat certain emulsions more advantageously and at a somewhat lower cost than is possible with other available demulsifiers, or conventional mixtures thereof. It is believed that the particular demulsifying agent or treating agent hereindescribed will find comparatively limited application, so far as the majority of oil field emulsions are concerned; but we have found that such a demulsifying agent has commercial value, as it will economically break or resolve oil field emulsions in a number of cases which cannot be treated as easily or at so low a cost with the demulsifying agents heretofore available.

In practising our process, a treating agent or demulsifier of the kind above described is brought into contact with or caused to act upon the emulsion to be treated, in any of the various ways, or by any of the various apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent, the above procedure being used either alone, or in combination with other demulsifying procedure, such as the electrical dehydration process.

The demulsifier herein contemplated may be employed in connection with what is commonly known as the down-the-hole procedure. i. e., bringing the demulsifier in contact with the fluids of the well at the bottom of the well or at some point prior to their emergence. This particular type of applicationis decidedly feasible when the demulsifier is used in connection with acidification of calcareous oil-bearing strata, especially if suspended in or dissolved in the acid employed for acidification.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier comprising a product of the kind derivable by an acylation reaction between: first, a ricinoleic acid body; and second, an acylation-reactive amine of the type:

B z \-CN/ I B 'r z in which B is selected from the class consisting of hydroxy hydrocarbon radicals, ether-type oxyhydrocarbon radicals, and hydroxylated ethertype oxvhydrocarbon radicals; T is selected from the class consisting of hydrogen atoms, alkyl radicals, and radicals of the kind exemplified by B; and Z represents a member of the class consisting of hydrogen atoms, hydrocarbon radicals, oxyhydrocarbon radicals, and radicals derived by removal of an alpha hydrogen atom from a carboxy acid ester.

2. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier comprising a product of the kind derivable by an acylation reaction between: first, a ricinoleic acid body; and second, an acylation-reactive amine of the following type:

B\ z c-N I B T z in which B is an alkylol radical; T is selected from the class consisting of hydrogen atoms, alkyl radicals, and radicalsot the kind exemplified by B; and Z represents a member 01 the class consisting of hydrogen atoms, hydrocarbon radicals, oxyhydrocarbon radicals, and radicals derived by removal of an alpha hydrogen atom from a carboxy acid ester.

3. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier comprising a product of the kind derivable by an acylation reaction between: first, a mainoleic acid body; and second, tris(hydroxymethyl) aminomethane.

4. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier comprising a product of the kind derivable by anacylation reaction between: first, a recinoleic acid body; and second, tris(hydroxymethyDaminomethane; said acylation product being primarily of the amide type.

5. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecti'ng the emulsion to the action of a demulsifier comprising a product, of the kind derivable by anacylation reaction between: first, a ricinoleic acid body; and second, tris(hydroxymethyDaminomethane; said acylation product being primarily of the ester type.

6. A process for breaking petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier comprising a product of the kind derivable by an acylation reaction between: first, a ricinoleic acid body; and second, tris(hydroxymethyl) aminomethane; said acylation product being primarily of the ester amide type.

MELVIN DE GROOTE. BERNHARD KEISER. 

